System of electrical distribution.



No. 629,898. Patented Aug. I, I899.

a. FERBARIS &. R. ABND.

SYSTEM OF ELECTRICAL DISTRIBUTION.

(Application filed Oct. 26, 1895.)

5 Sheen-Shoot I,

(No IQodoI.)

No. 629,898. Patented Aug. I899; G. FERBAR'IS &. R. ARNO.

SYSTEM OF ELECTRICAL DISTRIBUTION.

(Application filed Oct; 26, 1895.)

5 Shoots-Sheet 2.

No. 629,898. Patented Aug. 1, I899.

' G. FERRARIS & R. ARNO.

SYSTEM OF ELECTRICAL DISTRIBUTION.

(Application filed Oct. 26, 1895.) (No Model.) T 5 $heets$heoi a.

Fig. 7

No. 629,898. Patented Aug. I, I899.

a. rEninAms & n. ARNO.

SYSTEI 0F ELECTRICAL DISTRIBUTION.

. (Applicltionfll'ad Octfflfi, 1895,) (No Model.) 5 Sheets-Shoot 4.

' No. 629,898. Patented Aug. l, I899. s. FERRARIS & R. ABNO.

SYSTEM OF ELECTRICAL DISTRIBUTION.

' (Application filed on, 28, 1896 (No Model.) 5 Shoets-Shoet 5.

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UNITED STAT S I PATENT O FICE.

GALILEO FERRARIS AND RICCARDO ARNO, OF TURIN, ITALY.

SYSTEM OF ELECTRICAL DISTRIBUTION.

'SPEClFICATION forming part of Letters Patent No. 629,898, dated August1, 1899 Application filed October 26,1895 Serial No. 561007 (N0 model.)I

To (bl/1 10/1/0111, it may concern:

Be it known that we, GALILEO FERRARIS and RICOARDO ARNO, residing atTurin, Italy, have invented certain new and useful Improvements inSystems of Electrical Distribution; and we do hereby declare thefollowing to be a full, clear, and exact description of the invention,such as will enable others skilled in the art to which it appertains tomake and use the same, reference'being had to the accompanying drawings,and to letters and figures of reference marked thereon, which form apart of this specification.

Our invention relates to systems of electrical distribution, and isparticularly useful in cases where it is desired to furnish light andpower from the same main. By our improvements we are able to accomplishthis result with great convenience and efficiency and avoid theunbalancing troubles incident to commercial multiphase systems.

Our improved system is based on the useof a phase-displacingtransformer, and we prefer to use the transformer described in ourapplication Serial No. 547,975, though we are not in any way restrictedthereto. This transformer consists, broadly, of an inducing memher withseveral windings, one of them con 'nected to a source of sin gle-phasecurrent and an induced member preferably short-circuited. One of thesetwo members is capable of rotation relative to the other. It may, infact, be an ordinary single-phase induction-motor with extra coils woundon the inducing memher at an angle with the primary coils, so as tofurnish an out-'of-phase electromotive force.

In the drawings attached to this specification, Figure 1 is a diagram ofa biphase system of distriloution involving our improvements in a simpleform. Fig. 2 is a similar diagram of a biphase system in which thetransformer is connected direct to the hightension mains. Fig. 3 is adiagram of a biphase system in which the number of extra wires isreduced to one. Fig. 4 is a diagram of a similar interconnected biphasesystem. Fig. 5 is a diagram of an interconnected biphase system withlamps on'both sides. Fig. 6 is a diagram of a similar system in whichall the lamps are on the single-phase mains. Fig. 7 isa diagram of asystem in which. only primary current in the coil A A.

I one wire leads from the phase-displacing transformer: Figs. 8, 9,10,11, and 12 show various ways of obtaining and connecting threephasesystems with onlytwo coils on the phase-displacing transformer. Figs. 8,12 and 12 are explanatory diagrams showing the phases of the secondaryelectromotive forces in Figs. 8 and 12, respectively.

Like letters and figures refer to corresponding parts throughout thespecification.

In Fig. 1, O D represent wires connected to a source of singlealternating current. They may be the two mains of an ordinaryhightension single-phase system. P Q are the wires of the secondarynetwork, and T the phase-displacin g transformer. This transformer isshown as consisting of two coils-a primary A A and a secondary B B-whichare at right angles to each other, and a shortcircuited armature K,which is driven by the It is of course obvious that we intend to includewithin the scope of our invention well-known equivalents of our phasedisplacing transformer. If now a double conductor R S is led from theterminals of the secondary coil B B of the phase-displacing transformerT an alternating current of displaced phase is obtained upon the wires RS, which may be made of any voltage desired by suitably winding the coilB B; but in the system shown in this figure we prefer to make thevoltage on R S equal to that on P Q and displaced from it ninetydegrees. Thus a four-branched lowtension biphase system is obtained,consisting of the wires P Q R S, (be. It is evident that the wires P Qare equivalent to the wires P Q so far as phase is concerned, neglectingslight variations due to changes in load, and

phase-transformer so proportioned as to any i desired ratio oftransformation as to produce the desired voltage in the secondarycircuit from the given primary voltage. Thus a primary winding of verymany turns of fine wire with a secondary winding of a few turns of arelatively very coarse wire would obviously result in the production inthe secondary circuit of a materially decreased voltage and to increasedamperage. The proper ratio of transformationis determined by therequirements of any particular system. Otherwise the system is similarto that already described. But we prefer to provide an arrangement bywhich a single wire only need lead from the phase-displacing transformerto those of the translating devices requiring multiphase current.

Fig. 3' shows a system wherein the wires corresponding to the wires I QP Q &c., in Fig. 2 are joined in a continuous circuit and with the wiresR S, as shown in Fig. 2, changed to a single return-wire R by suitableintercommunication, as shown.

In Fig. I the wires corresponding to the wires P P, 850., in the otherfigures are joined, which is sufficient in many cases and results in asaving of copper. In this case the wire P between the subeenters orlocal distributing-points carries only the motor-current and should havethe same cross-section as that of the wire B.

Fig. 5 shows a method of conection in which -the secondaries of thetransformers T and T 5 are connected in series, and wires P Q R are ledoff from the terminals and from the intermediatepoiut.Itwillbeseenthatwehave here a three-wiresystem which differs from theordinary three-wire system in that the currents in the two sides aredisplaced in phase. Lamps may be placed as is usual in three-wiresystems, and the two transformers should preferably be of equal capacityand so built as to have the same secondary vol- 5 tages.

In Fig. 6 the same arrangement is shown, but the transformer T is of acapacity to supply its share of current to the multiphasetranslatingdevices only,and the single-phasetranslating devices are connected tothe leads which come from the transformer T only.

Fig. '7 is a combination of the devices shown in Figs. and 6, by whichthe amount of copper required may be still further reduced. 1

For producing three-phase currents several connections are possible.Fig. 8 shows perhaps the simplest and is to be read in connection withFig. 8. T is the single-phase transformer; M M, the three-phase motors;L Ii,thelamps,andT thephase-displacingtransformer. Let 1 5 in Fig. 8 bethe vector, representing in magnitude and phase the secondaryelectromotive force of the phase-displacing transformer. It will benoticed that the secondary of the transformer T is tapped in the centerby the wire S. Then the vector 3 4: will represent the electromot-iveforce of the secondary of T, ninety degrees in phase fromthatotlTheeleetromotivcforcefrom R to P is that of the phase-displacingtransformerplus halt'of that of the secondary winding of T, or, in thediagram, 1 5 plus 5 3 or 1 3, according to the usual rules for theaddition of vectors. The electromotive force from R to Q is l 5 minushalf 3 4, or 1 5 plus 5 4, or 1 :11. That between P and Q is 3 4;, whichis equal in magnitude to 1 3, and we have three sides of an equilateraltriangle and therefore a symmetrical three-phase system. \Vhen thetransformer-T is duplicated, the central points of all the secondariesshould be connected together, as shown in Fig. 9.

In Figs. 10 and 11 the phase-displacing transformers are connecteddirect to the hightension mains; but otherwise the systems are similarto those already described.

Fig. 12 and the corresponding diagram Figs. 12 and 12 show how athree-phase system may be obtained by placing on phasedisplacingtransformer a secondary coil at an acute or obtuse angle from theprimary. A A is the primary coil, and B the secondary, as before. Theelectrom otive force from P to Q may be represented by the vector6 7,Fig. 12, while the electromotive force from B to B or from Q to R may berepresented by 7 S. The resultant 8 6 will then represent theelectromotive force from P to B. This will be apparent when we considerthe various electromotive forces in connection with Figs. 12 and 12 Forexample, as the coil 6 b is the secondary winding of a transformer T wecan assume that its electromotive force will be approximately onehundred and eighty degreesdisplaced in direction from the electromotiveforce in the coil a a, the primary of the transformer T, and as theelectromotive force in B B acting in the circuit Q R is one hundred andtwenty degrees displaced from the current in the primary main-linecircuit or the current in A A it is obviously displaced two hundred andforty degrees from the electromotive force in the coil b b, and hence wecan, as above, represent the electromotive force in P Q as having thedirection I) Z), and the electromotive force in Q R by B B, and theresultant electromotive force by R P. As 13 is connected to b we can assume the line 7 S is connected to the line 6 '7 at the point 7, and oncompleting the triangle by making the eleetromotive forces of the properrelative amounts we have an equilateral triangle and a symmetricalthree-phase system.

As before stated, our invention as set forth in this application residesin a system of electrical distribution, and we do not limit ourselves toany specific transformer, but may use any dephasing-transformer whateverwhich will be suitable. Neither do we limit ourselves to the specificarrangements and conclaims we have used the expression ordinary.

transformer, by which we mean any trans former whatever which acts asdoes the commercial single phase transformerthat is, simply changesvoltage without reference to the lag of the currents or eleetromotiveforces. It is true that in the ordinary transformer the secondarycurrent is not in phase with the primary eleetromotive force, but as itis about one hundred and eighty degrees behind it the effect ispractically the same.

Ve claim as our invention- 1. In a single phase alternatingcurrentsystem, of electric distribution, the combination of the high-tensionmains, of an ordinary transformer, of the secondary conductors thereof,of a voltage and phase transformer having two relatively movableelements, one of which has Wound thereon coils closed upon themselvesconnected directly to the hightension mains, of a connection between thesecondary coil of the voltage and phasertransformer to the secondarycoil of the ordinary transformer, and of a single secondary conductorleading from the other terminal of the secondary coil of the voltage andphase transformer and forming with the secondary conductors'of theordinary transformer a threebranched two-phase low-tension system, substantially as described.

2. In an alternating-current system of elec tric distribution, thecombination of the hightension mains, of an ordinary transformer, of thesecondary conductors thereof, of a voltage and phase transformerconnected directly to the high-tension mains, of a connection betweenone terminal of the secondary coil of p the voltage and phasetransformer to the central point of the secondary coil of the ordinarytransformer, and of a single secondary conductor leading from the otherterminal of the secondary coil of the voltage and phase transformer andforming with the secondary conductors of the ordinary transformer athree-branched three-phase low-tension system, substantially asdescribed.

3. In a system of electrical distribution the combination of a pluralityof single-phase transformers, connections from the secondaries totranslating devices, a conductor joining one end of all of saidsecondaries, a tension and phase displacing transformer having primaryand secondary windings independent of each other, connected to the translating devices and the secondary mains, substantially as described.

4. In a system of electrical distribution, the combination of anordinary transformer, secondary conductors leading therefrom, a. tensionand phase displacing transformer having primary and secondary windings,and con having independent secondary windings, and

connections between the secondaries of said transformers wherebythree-phase currentis supplied to the translating devices, substantiallyas described.

8. In a system efelectrical distribution, the combination ofsingle-phase mains, an ordinary transformer connected thereto, secondaryconductors leading therefrom, a phasedisplacing transformer with itssecondary connected to the secondary network, and a conductor joiningpredetermined appropriate points in the secondaries of bothtransformers, substantially as described.

9. In a system of electrical distribution, the combination ofsingle-phase mains, a tension and phase displacing transformer havingrotary and stationary elements, a tension-reduction transformerconnected thereto, and a three-Wire system connected to the secondariesof said transformers, substantially as de scribed.

10. The method of producing multiphase currents from single-phasecurrents, which consists in generating alternating singlephase electriccurrents, transmitting them to any desired point or points, producing bythe said currents at the said point or points relative rotation ofmagnetic media with relation to each other, generating by the rotationof the said magnetic media out-of-phase electromotive forces orcurrents,combining said outof-phase electromotive forces or currents with theelectromotive forces or currents of the sin gle-phase system in properproportion so as to produce electromotive forces of a desired phaseangle, and so combining these electromotive forces in various circuitsas to produce in said circuits multiphase currents of a phase angle diiferent from that existing between the single-phase electrom otiveforces and the outof-phase electromotive forces.

11. The m ethod of producing multiphase currents from single-phasecurrents, which consistsin generating alternating singlephase electriccurrents, transmitting them to IIO phase electroniotive forces orcurrents with the clcctromotive forces or currents of the singlc-phasesystem in proper proportion so as to produce electromotive forces of adesired phase angle, and so combining these electromotive forces invarious circuits as to produce in said circuits multiphase currents of adif' ferent number of phases.

12. The method of producing multiphase currents from single-phasecurrents, which consists in generating alternating singlephase electriccurrent-s, transmitting them to any desired point or points, producingby the said currents at the said point or points relative rotation ofthe elements of an inductionmotor with relation to each other,generating by the rotation of the said elements of an induction-motorout-of-phasc elcctromotiye forces or currents, combining saidont-ofphase electromotive forces or currents with the electromotiveforces or currents of the single-phase system in proper proportion so asto produce eleetromotive forces of a desired phase angle, and socombining these electromotive forces in Various circuits as to producein said circuits multiphase currents of a difsecondary electromotiveforces to produce in circuits properly interrelated multiphase currentsof a different number of phases from the primary multiphaseelectromotive forces.

In testimony that we claim the foregoing as our invention we have signedour names in presence of two subscribing witnesses.

GALILEO FERRARIS. RICCARDO ARNO. Witnesses:

RAFFAELE RosE, Enortnno RIVOLTO.

